With demand for homes for social rent soaring in the capital and the supply of it slowing up, the private sector has increasingly filled the gap - with, of course, the help of housing benefit, or local housing allowance (LHA) as it is termed in this part of the housing jungle. LHA is, of course, being capped and cut back as part of the government's welfare reforms. The coalition's initial justification was to highlight the handful of atypical central London claimants receiving huge sums in LHA. Boris Johnson has long since preferred to point the finger at landlords.

On Wednesday he accused them of "creaming the system" and operating "a racket" by taking on claimant tenants at unreasonably high rents and letting the tax-payer pick up the bill. However, he went on, the government was providing him with "instruments to drive down their rents," by which he meant allowing more time before the measures took effect, permitting LHA to be paid directly to landlords, and providing funds to enable households deemed deserving to avoid immediately having to move somewhere cheaper.

But will landlords respond in the way proclaimed? A survey last December by Barking and Dagenham Council found those on its patch in buoyant mood: they anticipated a rise in demand for their properties from non-claimant households that would outweigh potential losses from LHA being reduced, because they wouldn't need claimant tenants in the first place.

Now a survey by the National Landlords Association raises the possibility that the capital's landlords as a whole are making ready to lessen their involvement with LHA claimants. The London part of the national survey it published last week, relates to 805 LHA tenancies in the capital. The results show that since January 28 percent of landlords responding to the survey had reduced the number of of LHA properties they let, 61 percent were planning to reduce their "LHA exposure" over the next two years, and 88 percent said they could not afford to cut their rents.

If these results are representative of all landlords in London, then the changes to LHA and their accompanying "transitional measures" will not drive rents down as the government and the Mayor assert but instead prompt a major withdrawal of landlords from the housing benefit market. The big question looms again. Where will all the poor people go?

I've spent much of today getting to grips with various recent reports and surveys relating to the many different dimensions of London's housing crisis, including the impact of welfare reform. I hope to share some of the fruits of my labours with you next week.